Operating a tire in aggressive environments such as off road conditions provides challenges in protecting the tire from damage. Obstacles such as rocks, trees, and other features provide threats to the tire not only along the tread region but also along the sidewall. While the tread region is designed to be in contact with the ground surface and is therefore constructed from compositions intended for this purpose, the sidewalls are generally not designed to be ground contacting. Instead, the sidewalls of a tire typically include a relatively thin layer of rubber material that covers certain structural elements, such as e.g., the cords of a tire carcass, which extend between and through the sidewalls of the tire. This rubber material is conventionally created from a composition not designed for ground contact but rather for flexibility so that the sidewalls can withstand the repeated flexing of the tire that occurs as it rotates through the contact patch. In addition, this sidewall rubber is typically not as thick as the tread rubber. As such, the sidewalls generally have less resistance than the tread to splitting or other puncture damage that can occur when the tire is contacted with an obstacle along the ground surface.
Certain tires are intended for more rugged applications where encounters with obstacles that may split or otherwise damage the sidewall can be frequent. For example, for recreational and emergency off-road applications, tires may be subjected to repeated contact with obstacles that can split the sidewall and damage or even deflate a pneumatic tire. Of course, for such tires, it is generally desirable to increase their capability to resist sidewall damage such as splitting, puncture, rupture, or other sidewall damaging events caused by contact during tire use.
Features can be added along the sidewall to help resist certain sidewall damage. Lugs, blocks, and/or other tread features can be added about the sidewall to protect it from aggression by remaining between a dangerous obstacle and the sidewall as the tire interacts with the obstacle during operation. The addition of features along the sidewall adds material, complexity, and expense to a tire. Such features can also unfavorably reduce the flexibility of the sidewall. Therefore, it is desirable to optimize the size and positioning of such features particularly when not all portions of the sidewall necessarily need protection. Also, such features along the sidewall can significantly alter the appearance of the tire. Consequently, aesthetic concerns play a significant role in determining the shape and location of features added to the sidewall.
Accordingly, a method for improving the resistance of a tire sidewall to damage from obstacles during tire operation is needed. More particularly, a method that can be used to determine the size and positioning of protective features along the sidewall of a tire so as to improve resistance to splitting, puncture, and other potential damage would be useful. A method that can also be used while adjusting such features for aesthetic considerations would be also be useful.